It can be a little tricky to change the password on a luggage lock if you've never done it. The best thing is to read the instruction manual or look up the model of your lock or suitcase on the internet, as each one is slightly different from the other. However, most work according to basic principles, usually using a button, lever or ring to reset.
Steps
Method 1 of 3: Changing a Reset Button Padlock

Step 1. First, open the lock
In general, your lock must have the correct password before you can change it. Enter the correct password and open.
The password probably came in the manual if the bag is new. It should be something like "000"

Step 2. Find the reset button
The lock usually has a small reset button underneath or to the side. You may need a paper clip, pen or pencil to push the button and start the reset.

Step 3. Enter your new password
While pressing the reset button, put your new password in the lock. Enter the password that works best for you, but choose one that is easy to remember.

Step 4. Release the button
When finished, release the button and you're done! You reset the lock. Remember to put the numbers in another combination to lock before you travel.
Method 2 of 3: Entering a New Password in a Lever Lock

Step 1. Find the lever
It can stay inside the suitcase. It could also be that it is outside, next to the numbers. Either way, you will need to know the current password before opening the case and zippers.

Step 2. Slide the lever to the reset position
The lever must be in this position for password change. Generally, you simply slide the lever to the second position.

Step 3. Change the password
Enter your new password in the lock. Choose something easy to remember and put the numbers in the correct position. Rotate each number to the desired position.

Step 4. Chain the suitcase by placing other random numbers
Push the lever back to the starting position. Check if the change worked by trying to open the suitcase with random numbers and then entering the chosen password. If it works, re-enter random numbers to lock the suitcase.
Method 3 of 3: Changing the Password of an External Lock

Step 1. Open the lock
It must be open first. Enter the correct password – probably "000" if it's new – and pull the loop open.

Step 2. Rotate the hoop 90 degrees and press it down
The way to turn the press will depend on the lock model. Start by turning 90 degrees from the default position. Press the loop and rotate another 90 degrees.
If the way explained above does not work, start by turning 180 degrees and then back 90 degrees. You will only know if it has actually reset if you enter a new password and try to open the lock with it

Step 3. Change the password
Enter the new password while the lock loop is still down.

Step 4. Finally, place the loop in its original position
After entering the new password, move the loop back to its original position. Check that the new password is working on the lock.